1. Field of the Invention
The invention pertains to a rocker arm arrangement of an internal combustion engine with a rocker arm and a bearing journal, where the bearing journal has an outside circumferential surface formed as a running surface and fits into a central bore of the rocker arm, which is lined with a bearing shell, so that the rocker arm is supported pivotably on the running surface of the bearing journal. The bearing journal has a first oil channel passing through its interior, which channel leads to at least one outlet at the running surface underneath the center longitudinal axis of the bearing journal. The bearing shell, which is permanently connected to the rocker arm, has a hollow cylindrical form with an outer shell surface and an inner shell surface.
2. Description of the Related Art
In the rocker arm arrangements of this type in current use, the bearing shell, which is also called a bearing bush, has internal grooves in its inner shell surface, i.e., in the inside circumferential surface facing the interior of the hollow cylinder. These grooves are connected to the first oil channel of the bearing journal. These grooves in the inside surface of the bearing shell are responsible for lubricating the running surface and also for distributing the lubricating oil to second oil channels, which extend inside the rocker arm and conduct the lubricating oil to secondary consumers. The latter include, for example, the contact point between the ball pressure unit mounted in the rocker arm and the tappet push rod and/or the components of an EVB (Exhaust Valve Brake), at least some of which are also installed in the connecting mechanism between the camshaft and the exhaust valves of an internal combustion engine.
When the play increases and/or under load, the gap between the bearing shell and the running surface of the bearing journal becomes larger in the area of the bearing facing away from the load, that is, in the area of the upper half of the bearing shell. In conjunction with the internal grooves, this enlarged gap leads to the loss of oil in the axial direction in the currently used rocker arm arrangements.